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IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)
e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 14, Issue 2 Ver. VII (Mar. - Apr. 2017), PP 52-66
www.iosrjournals.org
DOI: 10.9790/1684-1402075266 www.iosrjournals.org 52 | Page
Study on Properties of Self-Compacting Geopolymer Concrete
Ashraf Mohamed Henigal 1, Mohamed Amin Sherif
2, and
Hassan Hamouda Hassan 3
1, 2, 3(Civil Construction Dept., Faculty of Industrial Education/ Suez University, Suez, Egypt)
Abstract: The sustainable production ofself-compacting geopolymer concrete (SCGC) is an environment
friendly concrete which has lower carbon footprint as compared to that of conventional concrete. This paper
presents the study of the fresh and mechanical properties for self-compacting geopolymer concrete, In addition
to the physical properties. Some parameters were studied such as varying the molarity of sodium hydroxide
from 8M to 14M, ratio of sodium hydroxide to sodium silicate solution were between (1:2 to 1:2.75),alkaline
solution to fly ash ratio, extra water ratio, fly ash content was between 400 Kg/m3
to 500 Kg/m3, curing time,
and curing temperature. Compressive strength test was carried out at the ages of 3, 7, 28, and 91 days. The
others mechanical and physical properties tests were carried out at the age 28 days. The Increase of sodium
hydroxide molarity slightly reduces fresh properties of self-compacting geopolymer concrete. The mechanical
properties of self-compacting geopolymer concrete are only a fraction of the compressive strength, as in the
case of self-compacting concrete (SCC) with Portland cement. Increasing in the test results of physical
properties adversely affect it's the mechanical properties of self-compacting geopolymer concrete. Heat-cured
self-compacting geopolymer concrete undergoes very low drying shrinkage compared to that of self-compacting
concrete with ordinary Portland cement.
Keywords: Geopolymer, Self-Compacting, Fresh Properties, Compressive Strength, Dry Shrinkage
I. Introduction Concrete is one of the most far used construction materials in the world. Portland cement (PC); an
essential constituent of concrete is not an environmentally friendly material. The production of PC not only
depletes significant amount of natural resources but also liberates a considerable amount of carbon dioxide
(CO2) and other greenhouse gases in to the atmosphere as a result of decarbonation of limestone and the
combustion of fossil fuels. Self-compacting geopolymer concrete (SCGC) is relatively a new concept and can be
regarded as the most revolutionary development in the field of concrete technology. (SCGC) is an innovative
type of concrete that does not require vibration for placing it and can be produced by complete elimination of
ordinary Portland cement [1].
The use of geopolymer technology in making concrete has environmental benefit as it could reduce the
(CO2) emission to the atmosphere up to 80% compared to (OPC) concrete [2].
So, to reduce greenhouse gas emissions, efforts are needed to develop environmentally friendly construction
materials. The contribution of ordinary Portland cement (OPC) production worldwide to greenhouse gas
emissions is estimated to be approximately 1.35 billion tons annually or approximately 7% of the total
greenhouse gas emissions to the earth’s atmosphere. Also, it has been reported that many concrete structures,
especially those built in corrosive environments, start to deteriorate after 20 to 30 years, even though they have
been designed for more than 50 years of service life. In geopolymer concrete, a by-product material rich in
silicon and aluminum, such as low-calcium fly ash, is chemically activated by a high-alkaline solution to form a
paste that binds the loose coarse and fine aggregates and other unreacted materials in the mixture [3].
To preserve the global environment from the impact of cement production, it is imperative to search and explore
new possibilities to develop a concrete material that is more environmentally friendly as well as an efficient
construction material to replace conventional Portland cement concrete [4].
According to Nuruddin et al. [5] self-compacting geopolymer concrete (SCGC) can be considered as an
advanced and innovative construction material in the concrete technology. As the name implies, it does not need
any compacting efforts to achieve full compaction and utilizes fly ash together with alkaline solution and
superplasticizer as a binder for matrix formation and strength.
According to Omar Mohamed [6] indicated that the heat-cured fly ash-based geopolymer concrete undergoes
very low drying shrinkage from ordinary Portland cement concrete.
The main aim of this research study on fresh states, mechanical and physical properties of self-compacting
geopolymer concrete SCGC by utilizing locally available constituent materials.
Study on Properties of Self-Compacting Geopolymer Concrete
DOI: 10.9790/1684-1402075266 www.iosrjournals.org 53 | Page
II. Experimental work 2.1 Materials for concrete mixture
2.1.1 Fly ash
Fly ash is an industrial by-product of coal-fired power stations; the fly ash used in this research is classified as
class F fly ash according to the requirement of ASTM C618 Class F [7]. The chemical composition of fly ash as
determined by XRF is given in Table 1.
2.1.2 Cement
In this study, Ordinary Portland Cement (OPC) CEM I 42.5 N. produced by EL-Suez cement company
in Egypt was used as binder to produce of self-compacting concrete (SCC). Testing of cement was carried out as
the Egyptian Standard Specifications ESS 4756-1/2009 [8], with the specific gravity of 3.15 was used.
Table 1Chemicalcompositionofflyashas determinedby XRF Oxide By Mass % Requirements As Per ASTM C
618 Class F
Silicon dioxide (SiO2) 61.10 -----
Aluminum oxide (Al2O3) 28.60 -----
Ferric oxide (Fe2O3) 3.20 -----
Total (SiO2 + Al2O3 + Fe2O3) 92.90 Min. 70%
Calcium oxide (CaO) 1.40 -----
Magnesium oxide (MgO) 1.30 Max. 5%
Sulphur trioxide (SO3) 1.06 Max. 5%
Potassium oxide (K2O) 1.17 -----
Titanium dioxide (TiO2) 0.35 -----
Sodium oxide (Na2O) 0.76 Max. 1.5%
Total Chlorides (Cl) 0.03 Max. 0.05%
Loss on Ignition (LOI) 1.13 Max. 6%
2.1.3 Aggregates
Fine aggregate used in this experimental work was natural siliceous sand from (Suez area, Egypt),
clean and rounded fine aggregate with size 0.15 to 5 mm, a specific gravity of 2.67, a bulk unit weight of 1686
Kg/m3, and fineness modulus of 2.76. Three types of coarse aggregates were used in this research. These types
are local crushed limestone (dolomite), natural gravel, and crushed granite. The first type of local crushed
limestone (dolomite) with a specific gravity of 2.68, a bulk unit weight of 1619 Kg/m3, and maximum nominal
size of 10 mm was obtained from (Attaka Quarries, EL Suez area, Egypt), according to the requirement of ESS
1109/2002 [9]. The second type of coarse aggregates used in this research is natural gravel with a specific
gravity of 2.50, a bulk unit weight of 1537 Kg/m3, and maximum nominal size of 9 mm was obtained from
(Eleyn Elskhna, EL Suez area, Egypt). The third type of crushed granite was obtained from (Aswan area, Egypt)
with a specific gravity of 2.60, a bulk unit weight of 1564 Kg/m3, and maximum nominal size of 9 mm was
investigated as well.
2.1.4 Limestone powder
Limestone powder (LSP) was locally produced in Egypt having a specific gravity of 2.71, a color of white and
bulk unit weight of 1418 Kg/m3 was used.
2.1.5 Silica fume
In this research study, silica fume (SF) was locally produced in Egypt having a silica content of96.5%, a specific
gravity of 2.15, a color of light gray, a bulk unit weight of 392 Kg/m3 and specific surface area of20000 cm
2/gm
was used.
2.1.6 Superplasticizer
In order to achieve superior workability and required flowability of the fresh concrete, there is a
commercially available superplasticizer named as Sika Egypt Viscocrete-3425. It meets the requirements for
superplasticizer according to ASTM-C-494 Type G and BS EN 934 part 2: 2001, with a specific gravity of 1.08
and a color of clear liquid.
2.1.7 Alkaline solution
In geopolymer synthesis, alkaline solution plays an important role. In this study, a combination of
sodium hydroxide and sodium silicate was chosen as the alkaline liquid. Sodium Silicate Solution (SSS) was
obtained from (Suez area, Egypt). (Na2O = 14.6%, SiO2= 29.5% and water = 55.86% by mass), a specific
gravity 1.54 was used in this experimental work. Sodium Hydroxide Solution (SHS), analytical grade sodium
hydroxide in flake form (NaOH with 98-99% purity), was obtained from (6th of October City, Egypt). The
solids must be dissolved in water to make a solution with the required concentration. It is strongly recommended
that the sodium hydroxide solution must be prepared 24 hours prior to use. The concentration of sodium
Study on Properties of Self-Compacting Geopolymer Concrete
DOI: 10.9790/1684-1402075266 www.iosrjournals.org 54 | Page
hydroxide solution can vary in the range between 8 Molar and 14 Molar; however, 12 Molar solution is
adequate for most applications. The mass of NaOH solids in a solution varies depending on the concentration of
the solution. For instance, NaOH solution with a concentration of 12 Molar consists of 12 x 40 = 480 grams of
NaOH solids per liter of the water, where 40 is the molecular weight of NaOH. The mass of NaOH solids was
measured as 361grams per kg of NaOH solution and 639 grams of water with a concentration of 12 Molar.
2.1.8 Water
Specified amount of extra water was also used in the mix. The ordinary potable water available in the concrete
laboratory was used for this purpose.
2.2 Mix proportion
This experimental study program was designed to achieve the research objectives of the study. The
program consists of three mixtures of self compacting concrete were (A, B, andC) with Portland cement was
400 Kg/m3, 450 Kg/m
3, and 500 Kg/m
3, respectively. The coarse aggregate type of dolomite was used, fine to
coarse aggregates ratios were (45%: 55%). Limestone powder, silica fume, and superplasticizer dosage ratios
were 15%, 10%, and 4% respectively, as addition to cement content by weight in three mixtures. The water to
cementitious materials for mixtures A, B, C was (0.33, 0.32, and 0.30, respectively). Furthermore, thirty-two
mixtures of SCGC were prepared to assess the fresh state and studying the influence of various parameters on
the compressive strength at several cases curing (3, 7, 28, and 91 days) and splitting tensile strength, flexural
strength, bond strength, and modulus of elasticity at age 28 days for all mixtures. Only sixteen mixtures of them
were utilized to assess testing the water absorption, water permeability, and drying shrinkage. The details of
SCGC mixtures are given in Table 2.
Table2 Mixproportionsforself-compactinggeopolymerconcrete
2.3 Details of testing procedure
Filling ability, passing ability and resistance to segregation can be examined by the test methods. The
European Guidelines EFNARC has proposed different test methods to characterize an SCC mix. Test methods
and fresh state properties along with their recommended values given by EFNARC [10]. Compression test at
age 3, 7, 28, and 91 days is carried out on; 100×100×100 mm cubes, splitting tensile strength test at age 28 days
is carried out on; 150 × 300 mm cylinder, flexural strength test at age 28 days is carried out on; 100 × 100 × 500
mm prisms, bond strength test at age 28 days is carried out on; 150 × 300 mm cylinder, static modulus of
elasticity at age 28 days is carried out on; 150 × 300 mm cylinder, water permeability test at age28 days is
carried out on; 150 × 150 mm cylinder, water absorption test at age 28 days is carried out on; 100×100×100 mm
cubes, and test specimens for drying shrinkage test were 25 × 25 × 285 mm prisms at age 3, 7, 14, 21, 28, 56,
and 91 days.
Study on Properties of Self-Compacting Geopolymer Concrete
DOI: 10.9790/1684-1402075266 www.iosrjournals.org 55 | Page
2.4 Mixing procedure
The concrete mixing procedure consists of dry and wet mixing. Self-compacting concrete SCC was
mixed efficiently in a concrete drum mixer. The constituents were mixed in dry state for about three minutes to
ensure the uniformity of the mix. Mixing water and superplasticizer were added gradually and simultaneously
during mixing. All contents were mechanically mixed for about four extra minutes. The solid components of
SCGC, i.e. the fly ash and the fine and coarse aggregates, were dry mixed in the pan mixer for about three
minutes. The liquid part of the mixture, i.e. the sodium silicate solution, the sodium hydroxide solution, extra
water and the superplasticizer, were premixed thoroughly and then added to the dry mixture. The wet mixing
was done for four minutes. It was believed that the chemical reaction between alkaline solution, superplasticizer
and water took place and the reaction played an important role in giving the required fresh state for SCC and
SCGC and compressive strength of hardened concrete. The fresh state of SCC and SCGC had a flowing
consistency and with high tendency of filling ability, passing ability and resistance to segregation.
2.5 Casting and curing of test specimens
After mixing and assessing the necessary fresh properties as guided by EFNARC, the fresh concrete
was then filled into steel moulds and allowed to fill all the spaces of the moulds by its own self weight without
any compacting efforts. After casting, the SCC specimens were cured at water curing.Whereas the SCGC
specimens were put in an oven at different curing temperatures of (60 ºC, 70 ºC, and 80 ºC), and different curing
times of (24, 48, and 72 hours). The oven curing was followed by post curing by putting the specimens at
average room temperature of 24 ºC for one day stabilization period. The oven curing followed by post curing
was adopted in this research to accelerate geopolymerization process at elevated temperature and to enhance the
mechanical and physical properties performance. The reported of testing the mechanical and physical properties
is the average of three specimens. The test specimens were then left at average room temperature of 24 ºC until
the specified days of testing.
3 Test results and discussion
3.1 Fresh state tests of SCC and SCGC
To achieve the fresh state properties for each mix slump flow, slump flow at T50 cm, V-funnel at T0,
V-funnel at T5 minutes, L-Box (H2/H1), J-Ring, GTM screen stability, and air content tests were completed.
Every one of the tests was performed by taking after The European Rules for SCC, [10]. The test consequences
of fresh state properties are exhibited in Table 3.
3.1.1 Effect of cement content on the fresh state properties
Table 3 demonstrates the impact of concrete substance on the (SCC) mixtures with Portland cement. It
is for the most part acknowledged that the greater cement content in a concrete mixture, the more paste/coarse
aggregate proportion at a given mix proportioning. The three basic fresh properties required by SCC are Filling
Ability, Passing Ability and Segregation Resistance. Test comes about showed that, the utilization of 400 kg/m3
to 500 kg/m3 of cement content gave sensible aftereffects of fresh concrete properties.
3.1.2 Effect of coarse to fine aggregate ratio on the fresh state properties
The test outcomes appeared in Table 3 demonstratesthe variety in coarse to fine aggregate ratio were
between (60%:40%, 55%:45%, and 50%:50%)for mixtures M1, M2, and M3respectively, had somewhat impact
on the new properties of (SCGC).Slump flow for every one of the mixtures was inside the (EFNARC) scope of
650-800 mm. A greatest slump flow value of 710 mm was accomplished for a mixture having coarse to fine
aggregate ratio as (50%:50%).Expanding the coarse to fine aggregate ratio were between (60%:40%, 55%:45%,
and 50%:50%) the consistency of the arrangement was expanded. Thus, the flow of the concrete was diminished
up to 7.60%, which might be ascribed to the expansion of increasing the fine to coarse aggregate ratio.
3.1.3 Effect of alkaline solution to fly ash ratio on the fresh state properties
The test results shown in Table 3 indicate that the variation in alkaline solution to fly ash ratio were
between (0.3, 0.4, and 0.5) for mixtures M10, M11, and M2respectively, the J-Ring test shows the results of the
quantitative measurements and visual observations showed that it gave a good passing ability and the J-Ring
value especially at 0.5 alkaline solution to fly ash ratio for mixture M2
as compared to the other mixtures, was within the permissible limits of 0-10 mm given by (EFNARC). It was
observed that, for concrete mixture containing higher alkaline solution to fly ash ratio, the flowability and
passing ability of fresh concrete was increased as a result, J-Ring value was also reduced up to 50% due to the
increase in alkaline solution to fly ash ratio lead to enhance the flowability and passing ability.
3.1.4 Effect of variation of(SHS) to (SSS) ratio on the fresh state properties
The test results shown in Table 3 demonstrate that the variety of sodium hydroxide to sodium silicate
proportion solution were between (1:2, 1:2.25, 1:2.5, and 1:2.75) for mixtures M4, M5, M2, and M6
respectively. Test comes about T50 cm demonstrates a most minimal slump flow time (2 seconds) which
recorded for mixture M4 containing a proportion of sodium hydroxide to sodium silicate solution (1:2), was
Study on Properties of Self-Compacting Geopolymer Concrete
DOI: 10.9790/1684-1402075266 www.iosrjournals.org 56 | Page
diminished up to 33.3% when contrasted with alternate blends. Expanding the proportion of sodium hydroxide
to sodium silicate solution improves the consistency because of that high rate of Na2SiO3/NaOH which in part
prompts quickened disintegration of the strong materials and gave more durable, ease, and flowability of
(SCGC) mixtures.
3.1.5 Effect ofsodium hydroxide molarities on the fresh state properties
Table 3 demonstrates the molarity variety in sodium hydroxide from 8M to 14M for mixtures M7, M8,
M2, and M9 had somewhat impact on the new properties of (SCGC). The consequences of the quantitative
estimations and visual perceptions demonstrated that all the four blends had great passing ability and the J-Ring
an incentive for every one of the mixtures was inside the allowable furthest reaches of 0-10 mm given by
(EFNARC). A most minimal estimation of 4 mm was accomplished for the mixture containing 8M sodium
hydroxide molarity. Expanding the molarity of sodium hydroxide, the flowability and passing ability of fresh
concrete were lessened up to 50% which ascribed to the low rate of water-to-geopolymer solids proportion with
the increase in molarity of sodium hydroxide subsequently; J-Ring quality was likewise expanded.
3.1.6Effect of fly ash content on the fresh state properties
Table 3 demonstrates the consequences of variety of fly ash content that is between (400, 450, and 500
Kg/m3) for mixtures (M12, M21, and M24) with 5% superplasticizer dose, (M2, M22, and M25) with 6%
superplasticizer dose, and (M13, M23, and M26) with 7% superplasticizer dosage on the new properties of
(SCGC) mixtures. Also, the J-Ring test demonstrates the consequences of the quantitative estimations and visual
perceptions demonstrated that it gave a decent passing ability and the J-Ring esteem particularly at 500 Kg/m3
fly powder content with 7% superplasticizer dose for mixture M26 when contrasted with alternate mixtures, was
inside the admissible furthest reaches of 0-10 mm given by (EFNARC). It was noticed that for concrete
mixtures containing higher fly ash content, the flowability and passing ability of fresh concrete was expanded.
Therefore, J-Ring value was additionally lessened up to 33.3%due to the expansion in fly ash content with
higher SP dose prompt deflocculation and scattering of binder particles to improve the flowability and passing
ability.
Table 3Fresh state of test results for SCCand SCGC
Mix Code
Fresh state of test results
Slump Flow
Slump Flow T50 cm
V-Funnel T0
V-Funnel T5min
L-Box (H2/H1)
J-Ring GTM Screen
Stability
Air Content
(mm) (Sec.) (Sec.) (Sec.) Ratio (mm) % %
A 670 3 10 12 0.8 10 10 2.2
B 700 3 7 9 0.88 8 8 2.0
C 720 2 5 8 1.0 5 6 1.9
M1 660 6 11 15 0.92 7 2.2 3.0
M2 700 4 8 10 0.95 6 1.51 2.7
M3 710 3 7 9 0.96 5 1.42 2.6
M4 770 2 5 7 1.0 3 0.76 3.0
M5 750 4 7 9 0.97 5 1.54 2.8
M6 660 6 12 16 0.82 12 2.86 2.9
M7 740 3 6 8 0.98 4 0.93 2.5
M8 720 3 7 9 0.97 5 1.24 2.6
M9 670 5 10 14 0.90 8 2.34 2.8
M10 650 6 14 18 0.80 12 3.25 3.1
M11 680 5 12 15 0.87 10 2.61 3.0
M12 685 5 11 14 0.90 9 2.10 2.9
M13 720 4 7 9 0.96 5 1.52 2.6
M14 655 7 13 17 0.81 13 3.43 3.2
M15 720 4 7 9 0.96 5 1.32 2.6
M16 770 3 5 7 1.0 3 0.98 2.5
M17 700 4 8 10 0.95 6 1.51 2.7
M18 700 4 8 10 0.95 6 1.51 2.7
M19 700 4 8 10 0.95 6 1.51 2.7
M20 700 4 8 10 0.95 6 1.51 2.7
M21 695 5 10 14 0.92 7 1.86 2.8
M22 725 3 6 8 0.97 5 1.38 2.6
M23 750 3 5 7 1.0 4 0.91 2.4
M24 720 4 8 11 0.96 5 1.41 2.7
M25 745 3 5 7 0.98 4 0.97 2.5
M26 770 2 4 5 1.0 3 0.78 2.3
M27 710 4 7 10 0.95 5 1.47 2.6
M28 740 3 5 7 0.98 4 1.29 2.5
M29 765 2 4 6 0.99 4 0.91 2.5
M30 710 4 9 12 0.90 6 2.8 2.6
Study on Properties of Self-Compacting Geopolymer Concrete
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3.1.7 Effect of extra water ratio on the fresh state properties
Table 3 shows the variation in extra water ratio from (10%, 12%, 14%, and 16%) for mixtures (M14,
M2, M15, and M16)all the four mixtures showed almost good flowability and displayed a good resistance to
segregation of (SCGC). Slump flow for every one of the mixtures was inside the (EFNARC) scope of 650-800
mm.A greatest slump flow value of 770 mm was accomplished for a mixture having extra water ratio as
16%,the flow of the concrete was increased up to 17.6%, which may be attributed to the increase inpercentage
water, leading to improve the flowability.
3.1.8 Effect of coarse aggregate type on the fresh state properties
Table 3 delineated that the aftereffects of aggregate types (crushed dolomite, natural gravel, and
crushed granite) for mixtures (M2, M27, and M30) with fly ash content 400 Kg/m3, (M22, M28, and M31) with
fly ash content 450 Kg/m3, and (M25, M29, and M32) with fly ash content 500 Kg/m
3. V-funnel test at T0 for all
mixtures was inside as far as possible given by (EFNARC); a minimum flow time of 4 seconds was recorded for
mixtureM29 containingon natural gravel with fly ash content 500 Kg/m3. Therefore, the V-funnel flow time was
diminished up to 44.4% that might be ascribed to the natural gravel that gives the most astounding bond with
binder particles in light of the fact that the surface is smooth when contrasted with crushed dolomite and crushed
granite, in this manner has given more firm, smoothness and flowability. From the test outcomes delineated in
Table 3, which showed that the test aftereffects of fresh state for (SCGC) mixtures have given all the more good
consequences of fresh concrete.
3.2 Mechanical properties of SCGC
3.2.1 Compressive strength
3.2.1.1 Effect of coarse to fine aggregate ratio on the compressive strength Table 4 and Fig. 1outlined that the compressive strength of (SCGC) mixture containing on coarse to
fine aggregate ratio as (60%:40%) for blend M1 is higher than the compressive strength of mixtures prepared
with coarse to fine aggregate ratio were(55%:45%, and 50%:50%) for mixtures M2, and M3respectively, were
by around 2.6%, and 7.6% respectively, at 28 days age. This may be due to the increasing in coarse aggregate
ratio lead to more hardness for blend, thus gives compressive strength higher than the other blends.
3.2.1.2 Effect of alkaline solution to fly ash ratio on the compressive strength
The compressive strength of self-compacting geopolymer concrete containing on alkaline solution to
fly ash ratio of 0.5 for mixture M2 is higher than the compressive strength of the mixtures with alternate
proportions were (0.3, and 0.4) for mixtures M10, and M11 respectively, by around 39.6%, and 11.5%
respectively, at 28 days age. As outlined in Table 4 and Fig. 2 this increasing of compressive strength was
because of increase the liquid materials lead to quickly dissolution of the fly ash particles.
Table 4 Mechanical properties of test results for SCCand SCGC
M31 730 3 7 10 0.92 5 1.9 2.4
M32 760 3 5 8 0.94 5 1.46 2.3
Acceptance Criteria for SCC As Per EFNARC Guidelines [10]
Min. 650 2 6 6 + 0 0.8 0 0
Max. 800 5 12 12 + 3 1.0 10 15
Mix Code
Compressive Strength (MPa)
Splitting Tensile Strength
(MPa)
Flexural Strength (MPa)
Bond Strength (MPa)
Modulus of Elasticity
(GPa)
3d 7d 28d 91d 28d 28d 28d 28d
A 20.6 25.6 36.3 40.9 3.2 5.1 7.3 26.4
B 21.4 27.2 38.7 43.3 3.4 5.6 7.7 28.6
C 23.3 28.8 41.2 45.8 3.7 5.9 8.3 30.2
M1 41.7 44.0 46.7 48.8 5.4 7.7 9.40 38.8
M2 41.2 43.3 45.5 47.5 5.2 7.5 9.30 37.5
M3 40.2 40.6 43.4 45.4 4.8 7.3 9.0 36.1
M4 35.4 36.7 38.6 40.7 4.5 6.4 8.10 31.5
M5 38.8 40.2 42.5 45.3 5.1 7.2 8.80 35.5
M6 42.4 44.3 46.8 48.9 5.3 7.9 9.50 38.5
M7 33.0 34.9 36.5 37.5 4.0 5.9 7.60 32.0
M8 38.3 39.4 41.3 42.6 4.9 6.9 8.40 34.5
M9 43.4 44.4 47.6 49.8 5.6 8.1 9.80 39.0
M10 30.2 31.3 32.6 33.7 3.7 5.3 6.80 27.4
M11 37.5 38.9 40.8 42.2 4.6 6.7 8.30 33.5
M12 39.6 40.8 43.3 45.2 5.2 7.4 8.90 35.9
M13 42.9 44.9 47.2 49.3 5.4 7.8 9.70 38.6
Study on Properties of Self-Compacting Geopolymer Concrete
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Fig. 1 Effect of coarse to fine aggregate ratio on the compressive strength of SCGC
3.2.1.3 Effect of variation of SHS to SSS ratio on the compressive strength Table 4 and Fig. 3 outlined that the compressive strength of (SCGC) mixture containing on sodium
hydroxidesolution (SHS) to sodium silicatesolution (SSS) proportion of (1:2.75) for mixture M6 is higher than
the compressive strength of the mixtures with alternate proportions were (1:2, 1:2.25, and 1:2.5) for mixtures
(M4, M5, and M2) by around 21.2%, 10.1%, and 2.9% respectively, at 28 days age. This increasing of
compressive strength was because of sodium silicate activator, which breaks down quickly and fills the open
porosity by gel when the fluid stage could reach and start to bond the fly powder particle giving an enhancement
in compressive strength with the higher proportion of (SHS) to (SSS) which matches with B Tempest et al. [11].
Fig. 2 Effect of alkaline solution to fly ash ratio on the compressive strength of SCGC
M14 46.3 47.7 50.6 52.6 5.8 8.3 10.50 41.4
M15 36.6 37.2 39.5 40.8 4.5 6.4 8.20 32.9
M16 29.7 30.6 31.9 33.1 3.7 5.3 6.60 27.1
M17 38.8 40.1 42.4 44.2 4.9 6.8 8.70 35.0
M18 43.5 44.9 47.8 49.9 5.6 8.0 9.7 39.5
M19 39.6 41.0 43.3 44.9 4.9 7.1 8.95 35.8
M20 42.9 44.0 46.8 49.1 5.4 7.9 9.6 38.2
M21 44.0 43.2 45.6 47.4 5.4 7.7 9.40 37.7
M22 43.2 44.9 47.5 49.6 5.5 7.9 9.60 39.0
M23 44.3 46.3 48.9 51.1 5.6 8.2 10.20 40.2
M24 42.8 44.3 46.7 48.8 5.3 7.8 9.50 38.9
M25 44.2 45.9 48.6 50.7 5.6 8.2 9.90 40.5
M26 45.5 47.0 49.8 52.3 5.7 8.4 10.30 40.7
M27 37.3 38.6 40.5 42.2 4.6 6.7 8.30 33.9
M28 38.9 40.4 42.7 44.3 4.9 6.9 8.90 36.0
M29 39.4 41.1 43.2 45.2 5.0 7.2 8.95 36.4
M30 43.5 45.1 47.6 49.9 5.4 7.7 9.65 39.2
M31 44.7 46.4 49.1 51.2 5.7 8.3 10.10 41.0
M32 45.7 47.3 50.3 52.8 5.9 8.4 10.40 41.8
Study on Properties of Self-Compacting Geopolymer Concrete
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3.2.1.4 Effect of sodium hydroxide molarities on the compressive strength
Table 4 and Fig. 4 demonstrates the compressive strength of (SCGC) mixture containing on 14M for
blend M9 is higher than the compressive strength of mixtures prepared with 8M, 10M, and 12M for mixtures
M7, M8, and M2, were by around 30.4%, 15.3%, and 4.6% respectively, at 28 days age. The expansion in the
sodium hydroxide molarity prompted more dissolution of the solid materials and built geopolymerization
response and henceforth, higher compressive strength which matches with J.Temuujin et al. [12].
3.2.1.5 Effect of fly ash content on the compressive strength Table 4 and Fig. 5 represented that the compressive strength of (SCGC) mixture containing on fly ash
contents were (400, 450, and 500 Kg/m3) as (M13, M23, and M26) with 7% superplasticizer dose and crushed
dolomite is higher than the strength of mixtures (M12, M21, and M24) and (M2, M22, and M25) which
increment by around (6.6% to 9.0%) and (2.5% to 3.7%) of mixtures containing on 5%, and 6% superplasticizer
dose and crushed dolomite respectively, at 28 days age. This was because of the more compelling activity of the
superplasticizer with fly ash content in expanding the fresh state of the mixture. Pores and micro-cracks were
seen at lower SP dosages and fly ash content that could bring about decrease in the compressive strength. This
corresponds with Muhd Fadhil Nuruddin et al. [13].
Fig. 3 Effect of variation of SHS to SSS ratio on the compressive strength of SCGC
Fig. 4 Effect of sodium hydroxide molarities on the compressive strength of SCGC
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Fig. 5 Effect of fly ash content on the compressive strength of SCGC with dolomite
3.2.1.6 Effect of curing time on the compressive strength
Table 4 and Fig. 6 outlined that the compressive strength of (SCGC) mixture which cured in the oven
at a temperature of 70 °C for a time of 72 hours for mixture M18 is higher than the compressive strength of
mixtures cured in the oven at a temperature of 70 °C for 24, and 48 hours. The upgrade in compressive quality
for mixtures M17, and M2, was by around 12.7% and 5.1%, respectively, at 28 days age. This can be ascribed to
the more extended curing time that prompts the change of geopolymerization process giving higher coming
about compressive strength.
3.2.1.7 Effect of curing temperature on the compressive strength
Keeping in mind the end goal to concentrate the effect of curing temperature on the compressive
strength of (SCGC) mixtures M19, M2, and M20 were prepared. Except temperature, the various test parameters
were kept steady. In this study, the curing temperatures were changed from (60°C, 70°C, and80°C). From Table
4 and Fig.7 it was observed that blend M20, which cured at 80°C, for a time of 48 hours, created an upgrade of
the compressive strength contrasted with mixtures, which cured at 60°C and 70°C, by around 8.1% and
2.9%,respectively, at 28 days age. This upgrade was because of the high curing temperature, which in part,
prompts a snappier geopolymerization prepare that quickens the hardening of self-compacting geopolymer
concrete.
3.2.1.8 Effect of coarse aggregate type on the compressive strength
It can be seen from Table 4 and Fig. 8 that the compressive strength for mixtures containing on crushed
granite of mixtures (M30, M31, and M32) with 6% superplasticizer dose and fly ash contents were (400, 450,
and 500 Kg/m3) is higher than the compressive strength of mixtures arranged with natural gravel and crushed
dolomitewere (M27, M28, and M29) and (M2, M22, and M25) at the same superplasticizer dosage and fly ash
contents by around (17.5%, 15.0%, and 16.4%) and (4.6%, 3.4%, and 3.5%), respectively, at 28 days age. This
might be because of the crushed granite was more hardness, subsequently gives compressive strength higher
than the natural gravel and crushed dolomite.
3.2.1.9 Effect of extra water ratio on the compressive strength
It can be observed from Table 4 and Fig. 9 that the compressive strength of (SCGC) mixture containing
on 10%extra water for blend M14 is higher than the compressive strength of mixtures prepared with 12%, 14%,
and 16% extra waterfor blends M2, M15, and M16, were by around 11.2%, 28.1%, and 58.6% respectively, at
28 days age. This may be attributed to the increase in percentage extra water, subsequently leading to the
increasing in voids ratio for blendafter hardening that could cause reduction in the compressive strength.
In the earlier form test results illustrates in Table 4 it was observed that test results of compressive strength for
self-compacting geopolymer concrete (SCGC) mixtures given good results if compared to the self-compacting
concrete (SCC) mixtures with Portland cement.
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Fig. 6 Effect of curing time on the compressive strength of SCGC
Fig. 7 Effect of curing temperature on the compressive strength of SCGC
Fig. 8 Effect of coarse aggregate type on the compressive strength of SCGC
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Fig. 9 Effect of extra water ratio on the compressive strength of SCGC
3.2.2Splitting tensile strength
The test results of splitting tensile strength for 32 different SCGC mixtures are shown in Table 4 and
Fig. 10. The 28-days splitting tensile strength of SCGCranged from 3.7 to 5.9 MPa, the average value of
splitting tensile strength is about 11.5% from compressive strength. The analysis of test results yields the
following relationfor predicting the splitting tensile strength: (ƒsp28 = 0.1184ƒc28 - 0.1392).
3.2.3 Flexural strength
Table 4 and Fig. 11show the results of flexural strength for 32 different SCGC mixtures ranged from
5.3 to 8.4 MPa, the average value offlexural strength is about 16.6%from compressive strength. Also, it
appeared that the relation between experimental results of flexural strength and compressive strength is
independent of the 28-days agewas :( ƒr28 = 0.1756ƒc28 - 0.4144).
3.2.4 Bond strength
The 28-days bond strengthfor 32 different SCGC mixtures ranged from 6.6 to 10.5MPa, as shown in
Table 4. The average value of bond strength is about 20.6% from compressive strength. The relation between
bond strength and compressive strength is independent of the 28-days age was :(ƒb28 = 0.1993ƒc28 + 0.277), as
shown in Fig. 12.
3.2.5 Modulus of elasticity
The measurement of the modulus of elasticity for 32 different SCGC mixtures. The compressive
strength of these mixtures from 31.9 to 50.6 MPa, as shown in Table 4. Also, the measured modulus of elasticity
ranges from 27.1 to 41.8 GPa, the relation between modulus of elasticity and compressive strength is
independent of the 28-days age was :( Ec28 = 0.7729ƒc28 + 2.4947), as shown in Fig. 13.
3.3 Physical properties of SCGC
3.3.1 Permeability
To evaluate the water permeability of concrete, the apparatus subjects the concrete specimens to a
hydrostatic water pressure of 30 bars for a 24 hours period. Table 5 shows the coefficient of permeability for 16
different SCGC and SCC mixtures. The coefficient of permeability for different SCGC mixtures ranged from
0.7× 10-11
to 1.48 × 10-11
, the coefficient of permeability of SCGC can be reduced, because the microstructure of
SCGC denser. Whereas the coefficient of permeability values of mixtures prepared with SCC was 0.67 × 10-11
,
0.51 × 10-11
, and 0.47 × 10-11
cm/sec respectively (mixtures No; A, B, and C). It can be observed that the
coefficient of permeability decreases as the cement content increases. Fig. 14 indicate that the higher of test
results ofpermeability for 13 different SCGCmixtures may adversely affect its compressive strength, this can be
attributed to found the internal pores, consequently this leads to reduction in the microstructure of SCGC denser
and compressive strength.
3.3.2 Water absorption
To determine the water absorption of the specimens, three cubes from each series were taken after
curing at a temperature of 60 ºC for 24 hours, and all specimens were then stored in room temperature prior to
testing, and their weights were determined as initial weights. The samples were then immersed in water for 24
hours and their saturated surface dry weights were recorded as the final weights. Water absorption of specimens
is reported as the percentage of weight increases. The temperature was kept under 60 ºC to avoid any change in
the structural configuration which may be caused due to the exposure to a temperature over the curing one. The
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test results of water absorption for 16 different SCGC and SCC mixtures are shown in Table 5.From Fig.15 it
was observed that the increasing of test results ofwater absorption for 13 different SCGCmixtures may adversely
affect its compressive strength such as thepermeability. The water absorption for different SCGC mixtures
ranged from 2.24% to 3.01%. Whereas the water absorption values of mixtures prepared with SCC was 2.0%,
1.86%, and 1.75% respectively (mixtures No; A, B, and C).
3.3.3 Drying shrinkage Table 5 and Fig. 16demonstrate the plots of drying shrinkage strain versus age in days for the heat
cured test specimens. It can be seen that SCGC undergoes very low drying shrinkage compared to that of SCC
with ordinary Portland cement. The final value of drying shrinkage strain after 91 days period was only around
118 microstrain. In SCGC mixtures, most of the water released during the chemical reaction may evaporate
during the curing process, because the remaining water contained in the micro-pores of the hardened concrete is
small, the induced drying shrinkage is also very low.
Table 5 Physical properties of test results for SCCand SCGC
Fig. 10Splitting tensile strength versus compressive strength of SCGC
Mix
Code
Coefficient of Permeability,
K*10-11 (cm/sec)
Water Absorption % Drying Shrinkage (micro strain)
28d 28d 3d 7d 14d 21d 28d 56d 91d
A 0.67 2.0 80 175 230 290 305 395 450
B 0.51 1.86 90 190 270 305 325 420 480
C 0.47 1.75 95 198 285 315 340 435 490
M2 1.04 2.53 35 55 62 69 78 86 105
M4 1.35 2.92 28 48 56 63 73 80 93
M5 1.13 2.71 32 52 59 66 75 83 98
M6 0.87 2.45 40 60 65 74 80 90 110
M7 1.48 3.01 31 51 58 65 74 81 100
M8 1.05 2.75 33 54 60 67 76 84 102
M9 0.78 2.32 40 59 65 73 81 90 109
M17 1.13 2.65 44 63 68 77 87 98 118
M18 0.75 2.30 30 51 60 66 73 82 98
M22 0.77 2.32 40 60 67 73 83 90 110
M25 0.70 2.25 44 64 72 79 90 96 117
M28 1.12 2.62 37 56 61 70 80 88 107
M31 0.70 2.24 35 54 62 68 77 84 103
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Fig. 11Flexural strength versus compressive strength of SCGC
Fig. 12 Bond strength versus compressive strength of SCGC
Fig. 13Modulus of elasticity versus compressive strength of SCGC
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Fig. 14 Permeability versus compressive strength of SCGC
Fig. 15Water absorption versus compressive strength of SCGC
Fig. 16 Drying shrinkage of SCGC
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IV. Conclusions From the analysis and discussion of test results obtained from this research, the following conclusions can be
drawn:
1. Use of fly ash based self-compacting geopolymer concrete as an alternative binder can help reduce CO2
emission of concreteas compared to ordinary Portland cement.
2. The fresh state tests comes about demonstrate that an expansion in the molarity of sodium hydroxide
between 8M to 14M expanded the viscosity and cohesiveness of SCGC mixtures.
3. Utilizing fly ash contents in (SCGC) mixtures from 400 Kg/m3 to 500 Kg/m
3, enhanced the compressive
strength of self-compacting geopolymer concrete (SCGC) especially when superplasticizer dosages
increased.
4. Longer curing time between 24 to 72 hours at a temperature of 70°C enhances the geopolymerization
procedure bringing about higher compressive strength at early ages.
5. Higher value of compressive strength for SCGC reached to 52.8 MPa at age 91 days.
6. The mechanical properties of SCGC are only a fraction of the compressive strength, as in the case of SCC
with Portland cement.
7. Heat-cured SCGC undergoes very low drying shrinkage compared to that of SCC with ordinary Portland
cement.
8. The permeability and water absorption of the hardened SCGC decrease with the increase in compressive
strength of the SCGC.
References
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